Brown rice with chicken and broccoli. Sounds healthy, but recent research shows the dish may have a dark side: Rice, chicken, pork, apple juice, and some vegetables can have high levels of arsenic, a carcinogen also linked to heart disease.

A 'Consumer Reports' study discovered that 15 percent of 200-plus rice samples contained dangerous levels of arsenic, a heavy metal naturally found in groundwater. Arsenic becomes dangerous when concentrated into pesticides and spread over crops, such as rice. Researchers found that rice from Arkansas, Texas, and Louisiana consistently has the most arsenic. And the problem goes beyond rice. "Where there was widespread use of arsenical pesticides, there are huge amounts of arsenic now in our crops," says study author Michael Hansen, a senior scientist at the Consumers Union.

Hansen and other experts have asked the FDA to set standards on arsenic in food – none currently exist. But not everyone is panicking: Kit Kiefer, president of the Research Chefs Association, says the worry over arsenic is "a bit blown out of proportion. It takes an awful lot to cause a lot of damage compared with foodborne pathogens like E. coli and salmonella." Many scientists disagree. "When you're talking about a carcinogen like arsenic, there is no safe level," says Hansen. Some rice he tested had 200 parts per billion (ppb) to more than 900 ppb of arsenic – 20 to 90 times as much as the Environmental Protection Agency allows in drinking water. Earlier studies have found arsenic in chicken and pork at levels up to 21 ppb, mostly from arsenic-containing feed. And while there's less arsenic in chicken than in rice, there's concern that chicken and pig waste may contaminate food crops when used to fertilize land. Vegetables also contain arsenic, so much so that an EPA study found them to be the top source of arsenic in Americans' diet.